The day's highest-profile casualty of the day was Japan's eighth seed Kenichi Tago, who crashed out after a shock loss to Sri Lanka's Niluka Karunaratne.

Karunaratne, the world number 48, won 21-18 21-16 in 46 minutes, and Tago admitted he did not know what hit him.

He said: "It felt like I woke up from sleep and the next thing I know I had already lost. I don't know what happened."

The women's singles eighth seed Sung Ji-hyun of South Korea was also knocked out, going down 21-18 23-21 in a nailbiter to Hong Kong's world number 22 Yip Pui Yin.

The big guns in the women's singles had no such trouble.

Chinese pair Wang Yihan and Wang Xin, seeds one and two respectively, both reached the last 16 with comfortable wins in the morning session.

Visitors in the afternoon were robbed of a potentially thrilling finish in a men's doubles match between Thailand's Bodin Isara and Maneepong Jongjit and the Poles Adam Cwalina and Michal Logosz.

The Polish pair were trailing 17-15 in a deciding game when Logosz snapped an Achilles tendon landing awkwardly after jumping.

He left the arena in a wheelchair and the Thais won by default.

America's 2005 world champions Howard Bach, 33, and Tony Gunawan, 37, announced their retirement after going down to a third successive loss in the men's doubles, this time to Japan's Naoki Kawamae and Shoji Sato.

Bach said: "I'm ready to call it a day. Well never say never I suppose but there is a 0.00000% chance I may be back."

Korean Lee Yong-dae saw his hopes of defending the mixed doubles title ended as he and new partner Ha Jung-eun lost 21-15 21-12 to Danes Thomas Laybourn and Kamilla Rytter Juhl.